Call:
lm(formula = y ~ x)

Residuals:
     Min       1Q   Median       3Q      Max 
-0.09023 -0.08506 -0.01012 -0.00026  0.66324 

Coefficients:
                      Estimate Std. Error t value             Pr(>|t|)    
(Intercept)           0.090233   0.007459  12.097 < 0.0000000000000002 ***
xLow income          -0.090097   0.016790  -5.366      0.0000001091390 ***
xLower middle income -0.089948   0.013501  -6.662      0.0000000000542 ***
xNA                  -0.021484   0.025723  -0.835                0.404    
xUpper middle income -0.080101   0.012468  -6.424      0.0000000002432 ***
---
Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1

Residual standard error: 0.1303 on 707 degrees of freedom
Multiple R-squared:  0.09534,	Adjusted R-squared:  0.09022 
F-statistic: 18.63 on 4 and 707 DF,  p-value: 0.00000000000001437